summaryrefslogtreecommitdiffstats
path: root/ds9/doc/ref/bin.html
blob: 667687969aae0127eb3455d59e56601590041b46 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
<!DOCTYPE doctype PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<meta name="generator" content="HTML Tidy for Mac OS X (vers 31 October 2006 - Apple Inc. build 16.1), see www.w3.org">
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="GENERATOR" content="Mozilla/4.78 [en] (X11; U; Linux 2.4.7-10 i686) [Netscape]">
<title>Bin</title>
</head>
<body alink="#FF0000" bgcolor="#FFFFFF" link="#0000EE" text="#000000" vlink="#551A8B">
<h3><img alt="" src="../sun.gif" align="middle" height="98" width="100"> Binning</h3>
<blockquote>
<p>To create an image from a FITS Bin Table, the user needs to specify a binning factor, binning buffer size, and the binning function.<br></p>
<p>The Binning (or Block) Factor is defined as the following: A value greater or equal to zero. This value indicates the number of pixel values that will fall into a particular bin.<br></p>
<p>The Bin Buffer Size is overall size of the image generated. This has no relation to min and max values of the columns used to create the image.<br></p>
<p>The Bin Function is defined as the following: Average - all pixel values that fall into one pixel bin are averaged. Sum - all pixel values that fall into one pixel bin are summed.<br></p>
<p>Bin to Fit Frame will calculate a bin block factor as a power of 2 that will allow the entire data space to be displayed in the current frame.</p>
<p>By default, DS9 will bin about the center of the image. To determine the center of the image, DS9 will look for the following keywords in order:</p>
<blockquote><tt>TDMIN/TDMAX<br>
TLMIN/TLMAX<br>
TALEN<br>
AXLEN</tt></blockquote>
<p>If no valid keywords are found, DS9 will define the center as the middle of the possible data space based on the coordinate data type.</p>
<br>
<p><br></p>
<p><br></p>
<br></blockquote>
</body>
</html>